mcnab



Oct. 15, 1929. A, CNAB 1,731,254

- JACK Filed May 2. 1927 3 Sheets-Sheet 3 INVENTOR ATTORNEYS Panarea oct. 15,1929

UNITED STATES- ALEXANDERMONAB.- or Naw Yoan', or NEW Yoan, N. Y.,

JACK

Application filed May 2, 1927. Serial No. 188,213.

This invention relates to lifting jacksand particularly to lifting jacks for vehicles.

The use of jacks for raising vehicles is often attended with a certain 'amount of diiiiculty as is well known.` Automobiles for Vinstance, diier in ground clearance both of the back and front axles and in the construction o the axles, one or two points on the rear aXle which will atl'ord a purchase for a jack.

It is diflicult to rovide a jack of a construction such that axles of different construction -can be etliciently handled by the same jack,

l gested and in this labor. Further, aportion of the work thathas to be done is wasted in that the carhas often to be lifted a considerable distance before taking up the slackin the springs and tires, while in cars using over-size or balloon tires, the distance to which the car must be lifted is still further increased:

The general object of the invention 1s to provide a iuid pressure jack of compact form and more eiiicient construction than those yhitherto proposed or constructed, designed to overcome or reduce to a minimum the dlsadvantages above mentioned.

One object of the invention is to provide an improved hydraulic jackoperated by fluid I pressure supplied by an engine driven pump.

Another object of the invention is to provide an engine driven hydraulic jack provid.

in a maximum lift in minimum height of lac Astill further ob]ect of the mventlon 1s to provide a jack'which may he readily attached to axles of widely diierent ground clearance.

and in some cars there are only A still further object ofthe invention is t0 provide improved controlling means for said jacks whe'reby a plurality of jacks perma nently attached to a motor vehiclemay be operated from the vehicle to raise any wheel of the car or any two or all four wheels of the car as desired.

A still further object of the invention is tol provide a jack comprising a minimum number of moving parts and of robust and simple construction. v

In the accompanying drawings various specific embodiments of the invention are described and illustrated, but lit is to be under stood that the scope of the invention is'not limited in an wayby the embodimentsdescribed and illust-rated, but only as determined by the appended claims,

Figure 1 is a View m elevation of the jack inportable form, partly in section.

Figure 2 is a sectional view of the jack shown in Figure l in fully extendedposition.

Figure 3 is an elevation of the ump.

Fig. 4 shows a control mounted) on the dash for a set ofjacks permanently mounted on the axles of an automobile.

Fig. 5 is a section on line 5-5 of Fig. 4.

Fig. 6 is a section on line 6-6 of Fig. 5.

Fig. 7 is a perspective view of the clutch arm control. i

Fig. 8 is a diagrammatic viewl showing an automobile having two of the novel jacks mounted on the front axle, two'others being similarly mounted on the rear axle.

Fig. 10 is a detail of the ybracket arm mounted on the jack.

In the following description the speciicv form of jack referred to is one that may be carried in a tool box or used for heavy duty in a garage. In this form the pressure iiuid would be led to a convenient point at which outlets would be arranged,'such outlets being controlled by an ordinary cock arrangedto connect the supply and return pipes of the s pressure line with the supply and return valves arranged on the jack,'or to rclose the-1100*Y 'connections to the jack and connect the two Y sid-es of the pressure line'.

. The .jack `would in such cases preferably be provided with a length of flexible high pressure tubing ending in a connectin member adapted to be readily clamped to flic outlet,

the valve arranged on the head of the jack enablin the latter to be controlled in situ.

For ilustrative purposes the ball checks have been shown as arranged on the jack, but they would of course` be normally arranged in the coupling member attached to the jack pipe connection.

at 3, and 4' is a tube connecting the inlet 3 and the valve housinof 5, invwhich is mounted a plug which may be operated by the handle 6. 8 indicates the pressure pipe connection, and 9 the return pipe connection to the valve hous- The lower end of the cylinder 1 is closed by a combined packing gland and bearing` member 10.'v Within .the cylinder 1 is arranged a main piston 11 having a head 11a.

This piston is hollow and nestedwithin it is an auxiliary piston 12 which extends'throughl a member 13 closing the outer end of the main piston 11 and which is provided with a 'head l2a formed similarlyto the member v16.

' The piston 12 carries at its lower end a ball foot 14 clamped in a divided ball shaped socket 15 which is as shown in the ldrawing integral with a foot portion. The main piston 11 is turned down below its head portion to form a recess 17, and the travel ofthe pis-4 ton in the cylinder 1 is limited by the upstanding fiange 18 of the nut 18. The auxiliary piston 12 is similarly turned down to provide a recess 19 and its travel in the piston 11 is limited by the upstanding flange 20 of nut 20. The wall of the main lpiston is sufficiently thick to afford a sturdy support to the inner piston, andto 'carry passages 16 formed therein, These passages communicate with the space 17 at its upper end, and with the space' 19 at its lower end. Pump washers 22 are clamped vto the members 10 and 13 by means of the nuts 18 and 20which are screwed down upon said Washers. It will be observed that the passages 16 extend through the outer end of the wall 21 and are'closed by the nut' 20. This construction enables the assages to be'readily cleaned by the insertion of a wire after removal of the member 13. It will. be also noticed that the flanges of nuts 18 and 2O do not extend to the surface of the walls 21 and 7, and are provided with bores opposite As shown in Fig the lower 'ends of the ducts 4and '16 respectively, this arrangement enabling the pres sure fluid to reach the spaces A17 and 19 when the pistons are in fully extended position as shown in Figure 2.

The operation of this part of the apparatus will, it is believed, be clear. Pressure fluid such as oil being admitted to the cylinder 24, the pistons will be extended at a rate dependent upon the speed of the engine. If this is high, thel pump will be delivering a relatively large amount-of fluid and the pistons will extend rapidly, the speed of extension decreasing as the load increases with the resistance offered to the movement ofthe pistons, the outer piston being arrested by engaging the ring 18 and the inner piston by engaglng the ring 20', which will occur, of course, only when both pistons are fully eX- tended.

One of the principal features of novelty of the jack resides in the means provided for retracting the pistons into nested relation. While in the hydraulic jackof usual construction the return of the piston to greater or lesser degree according to the ground clearance of the car would be effected fairly rapidly by the weight of the car, the piston would still be left hard up against the axle and dimculty might be experienced in dislodging the jack from this position, since owing to `the necessarily close fit of the pistons in the cylinders considerable effort has to be expended to force the piston into the cylinder.

According to my invention, the pistons may 10o be -completely returned by pressure fiui This is effected in the portable form of the pump by turning the valve by the'handle 6 to connect the cylinder space 24 with -the return pipe 9 and pressurepipe 8 through the los port 3 with the spaces 17 and 19. The pistons will be rapidly returned vinwardly until stopped by the plug 18 coming against the part 10 and a ring 25 against the part 13. ln order to -prevent oil from being-spilled fromthe 11e jack, the connectionson the valve casingare preferably provided lwith ball valves ar. ranged in housings projecting from the Casing, though of course such ballvalves mi ht j also be arranged in the connectm .mem er 115'` pressure 1 serving to attach the ack to the fihi outlet.

the cylinder is provided with corrugations 26'.

These corrugations act to support an adjust-12p able arm or bracket 27 formed by the project- -ing ends 28 of a band 29 of springysteel, and

serve the purpose of insuring the secure positioning of the arm on the cylinder when once adjusted.

It will be readilyAh understoody Ythat the bracket may be so constructed that it may be adjusted even after the pipe 4 is in position.

For instance the bracket might be formed from spring steel, and, if desired bosses might 1, the outer surface vof".

'be arranged' on the 'projecting portion forming the arm of the bracket, and these bosses bored and tap ed with opposite threads coacting with a bolt having opposite threaded ends so that on slacking back the bolt the band of the bracket extending around the cylinder would increase in diameter suliicient ly to be slipped over one or more corrugations until the desired position was reached, whereupon the nut could be ti htened up thereby contracting the band 29 a out the cylinder.

If the jack ,'s to be permanently attached to a part ofthe vehicle, such as the axle, the band 29l could, of course, bolted to the a-xle or otherwise secured thereto. In order to supply lluid under pressure to operate the 'jack in the manner hereinbefore i described, a pump such as illustrated in lFigure 3 may be advantageously utilized. This pump hasa main pumping c linder containing an operating plunger w ich is actuated by a cam 33 of varying throw and by a lcontrolling cylinder 34 in communication with the pressure system on the jack side of an outlet valve 35 of the pump. The controlling cylinder 34 acts through a plunger 36 and lever 37 to adiust the position of the cam`33, according to the load against which the pump is working, in opposit1on expansion spring 38. The pump may be driven from any suitable source of power, and in cases'where the jacking system is installed on an automobile as part'of the running equipment the p'ump is driven through a clutch by control mechanism as hereinafter described.

Figure 4 shows-a convenient control arrangement for a jacking system comprising four jacks. The control is adapted to be mounted on the dash and comprises four separate small levers- 56 each controlling a -j ack and adapted to be locked in operative or inoperative positionby a bar 57 the depression of which serves to efect the clutching of the pump shaft to the driving means.

The construction of the bar 57 in therform illustrated is suchthat when in a depressed position any of the levers 56 may be manipulated independently of the others or-a portion of. the bar while still in its u per position can be operated to'move all our levers to operative position` the bar bein thereafter depressed to clutch the pump ell engine.

The bar 57 may be of a T section mounted at each end on arms 58 pivoted at 59 on the dash and having anup and down movementonly.

The horizontal section ofthe bar 57 is pro# vided with notches 60, the left hand edges of which form abutments 61 adaptedt come against the sides ofthelevers 56. Mounted to slide on the horizontal section ofthe bar is a flat bar 62 provided at oneend with a handle 63 and normally held to overlie the be shaped to bev 'are in inoperative position,

to the ell'ort of an v one set of aft to the 'car to operate the lacks 'locked in lowered position.

horizontal portion 'of .the T yshaped bar by Va vstrong spring 64 holding the opposite edge 66 against the levers 56. The bar is guided for a-sliding movement on 57 by a pin and slot mounting.

The flat bar 62 is also provided with notches 65, the left hand edges of, which, as seen in Fig. 7, form abutments 66 coming against the sides of the levers 56 on the same side as that on which the edges 61 of the notches in the clutch bar engage the levers.

By`displacing the bar 62 as described, to the left as seen in Fig. 7, the levers are swung to the operative position, 57 Vvand 62 may be depressed to -put in the pump clutch.

Return of the clutch bar to its upper position cannot take place until all the levers 56 since the ends of the levers will come over a solid portion of the flat bar. j

The valves controlling the flow of fluid to the jacks are of ordinary form being provided with conduits interruptingor making communication between the pump pressure and return pipes and the pipes conveying the working fluid to and from the upper or lower sides of the jack pistons.

The valves could be mounted on a plate 67 carrying the levers 56 or could be mounted on a second plate 68, adapted to be attached to the rear of the dash as shown in the drawings, and also serving to carry the pivots for the clutch bar, the valve spindles projecting through the dash and the plate 67.

Fig. 8 is a viewshowing how two of the jacks .may conveniently be mounted on the front axle of a car, two jacks being similarly.

after which the bars alsl or tWo or four points simultaneously p1t` might be desired for instance, to change-from on' all four wheels atonce.

tended period.l

also be utilized as a safety device when leav-v ing the car parked'in av ublic place, since it would be almost impossi le to break into the without attracting attention'. Further ltlwould'be a siinle mat#` ter to provide a combination or ot by'which the clutch'operatingbar could be kIt would not of course, be. necessary to declutch the pump er lock i l tires'to another in which-case much -l ltime would be saved b y operating all ,fours i Jacks thus enabling garage mechanics tofwork when leaving the car under these circumstances, since the engine would be switched off.

It will be realized that a jack construction and operating system according to the invention provides a considerable improvement on those commonly in use. The construction ofV `the jacks and ofy pump and of the control means is simple, efficient and reliable, and can be cheaply manufactured to provide a very attractive construction.

l. An hydraulic jack comprising a cylinder, a plurality of pistons within said cylinder arranged one within the other, conduits for supplying fluid under pressure to the upper or lower sides of the heads of said pistons, said conduits communicating with spaces Vbetween the cylinder` ends and said pistons through channels arranged upon the wall of the outer piston.

2. An hydraulic jack comprising a cylinder, a plurality ofpistons within said cylinder arranged one within the' other, conduits for the supply of pressure fluid to spacesl above and below the heads of said pistons, and channels arranged within the wall of the outer piston communicating at one end with a space below the head of the outer piston and communicating at the other end with a space located below the inner piston head.

3. An hydraulic jack comprising acylinder, a plurality of pistons within said cylinder arranged one within the other, conduits for the supply ofpressure fluid to spaces above and below the heads of said pistons, and

channels arranged within the wall of theouter piston communicating at their upper ends adjacent to and below the head of the outer piston and communicating at their lower ends with a space between the surface of the innery piston4 and the surface of the outer piston.

4. An hydraulic 'ack comprising a piston land a cylinder -wit in which said piston is ada ted to reciprocate, a second piston mounted or movement in thefirst piston and adapted to be extended into engagement with the surface on which the vehicle to be jacked rests, conduits for the supply of pressure Huid to spaces above and below the heads of said pistons, and channels extending longitudinally within the Wall of the outer piston and l adapted to communicate at one end with a space between the outer surface of the first mentioned 4piston and the inner surface of the cylinder and at the other end with a space between the outer surface of the inner piston and the inner surface of the first mentioned piston.

5. An hydraulic jack. system comprising a pluralit of jacks, means .driven by a prime mover or supplying fluid under pressure, clutch-'mechanism whereby said prime mover may be connected to or disconnected from `ment until said/control means have again been brought into a position to cut. 'ofi' the supply of fluid to the jacks. y

' 6. An hydraulic jack system comprising means for lsupplying fluid under pressure, a plurality ofjacks each of which comprises a cylinder, piston means mounted within said cylinder, and conduits for -supplying fluid under pressure between the cylinder and said piston means, clutch mechanism for connecting or disconnecting each o r all of said cyl- 'inders from said means for supplying fluid under pressure, valve means for controlling the flow of fluid to each of said jacks, interconnecting means interposed between said clutch mechanism and said controlling means,

said interconnecting means comprising a member acting normally to hold said controlling means 1n inoperative position but movable to allow operation of said latter means, l

said control means acting to hold the clutch mechanism in position to maintain the clutch in engagement until said control means have again been brought into a position to cut off the' supply of fluid to the jacks.

In testimony whereof I have affixed my signature.

ALEXANDER MCNAB.

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